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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 19 patients with unilateral renal artery stenosis and subsequent renovascular hypertension plasma renin activity (PRA), plasma concentrations of atrial natriuretic peptide (ANP), erythropoietin (Epo), H+ and HCO3-, as well as pO2 and pCO2 were assessed in renal venous blood of the 'ischaemic' and normally perfused kidney, both in arterial blood and in the inferior vena cava distally from the orifices of the renal veins. PRA and ANP were significantly elevated in venous blood of the ischaemic kidney as compared with the normally perfused kidney. In contrast to PRA and ANP, plasma concentrations of Epo were similar in blood withdrawn at all vascular sites. pO2 and pCO2, as well as blood H+ and HCO3- concentrations in venous blood of the ischaemic kidney were of the same magnitude as of the normally perfused kidney. From the results presented in this paper it follows that (i) in contrast to plasma renin activity and ANP, unilateral renal 'ischaemia' does not influence plasma concentrations of Epo in renal venous blood, and (ii) chronic haemodynamic alterations do not seem to influence Epo secretion by the kidneys.
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PMID:Plasma erythropoietin concentrations in renal venous blood of patients with unilateral renovascular hypertension. 131 93

Systemic hypertension as assessed by causal blood pressure measurements is a frequently reported side-effect of recombinant human erythropoietin (rHuEpo) treatment. We investigated the effect of rHuEpo treatment on the 24-h ambulatory blood pressure and heart rate profiles of 13 chronic haemodialysis patients. After 3-4 months of rHuEpo therapy it was found that the mean haematocrit had increased from 24.5 +/- 1.0% to 32.0 +/- 1.1% (P less than 0.005), while body-weight and control of uraemia as assessed by routine laboratory data remained unchanged. Despite gradual and incomplete correction of anaemia by use of low doses of rHuEpo, increases in the ambulatory systolic and diastolic blood pressure were found. The greatest increases affected day-time systolic blood pressure and night-time diastolic blood pressure, and these increases were significant (P less than 0.05). As a result, pulse pressure increased during day-time (P less than 0.05) while the night-time decline in diastolic blood pressure disappeared. An increase in peripheral resistance after partial correction of renal anaemia might explain these observations. rHuEpo therapy increased the percentage of abnormal ambulatory blood pressure measurements (defined as systolic blood pressure greater than 140 mmHg and/or diastolic blood pressure greater than 90 mmHg) from 33% to 52% (P less than 0.05) while in contrast, mean casual prehaemodialytic and posthaemodialytic blood pressure values remained unchanged. We conclude that changes in 24-h blood pressure profiles should be carefully assessed by ambulatory blood pressure monitoring in haemodialysis patients treated with rHuEpo, since these changes are likely to be missed when only causal blood pressures are measured.
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PMID:Effect of recombinant human erythropoietin therapy on ambulatory blood pressure and heart rate in chronic haemodialysis patients. 131 80

The relationship between the renin-angiotensin system and erythropoietin was studied in twenty patients with renal artery stenosis and hypertension. Ten of the patients had a unilaterally activated renin-angiotensin system (group 1), while ten patients had not (group 2). Plasma erythropoietin was simultaneously measured in a brachial artery and both renal veins before and 5 and 30 min after an intravenous injection of 1.25 mg enalaprilat. The mean (+/- SD) arterial erythropoietin concentration was 27.3 +/- 16.8 mU/ml in group 1 and 14.1 +/- 11.3 mU/ml in group 2 patients (P less than 0.05). There was no significant change after enalaprilat i.v. in either group. The venous erythropoietin concentration in plasma from the stenotic kidney did not differ from that of the contralateral kidney. The higher erythropoietin concentration in group 1 patients may be explained by a systemic stimulatory effect of the renin-angiotensin system on erythropoietin production. As no side-differences were found, renal vein as well as peripheral erythropoietin measurements cannot be used as a tool in the diagnosis of the functional significance of a renal artery stenosis.
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PMID:Diagnostic use of renal vein erythropoietin measurements in patients with renal artery stenosis. 132 75

It has been 6 years since the first reports of the use of recombinant human erythropoietin for the treatment of renal anemia appeared in the medical literature. During this period, erythropoietin has become established as a safe and highly effective therapy, and it is currently being evaluated for other nonrenal types of anemia. The initial clinical trials were in hemodialysis patients, followed by patients receiving continuous ambulatory peritoneal dialysis, and its use in predialysis and renal transplant patients is increasing. Various treatment schedules have been tried and compared; there are now reports of dosage frequencies varying from once daily to once weekly. Information has accumulated on the secondary effects of correction of renal anemia, particularly in relation to quality of life, exercise capacity, and cardiac function. Large multicenter trials have documented the safety profile of erythropoietin, whereas smaller studies have sought to elucidate the pathophysiology of its side effects, eg, hypertension and thrombotic events. This article reviews the latest developments in the use of erythropoietin in renal failure, concentrating particularly on those that have been published within the past year. Although there have been exciting advances in our understanding of the physiology and molecular biology of erythropoietin, these are amply described elsewhere and are beyond the scope of the present review.
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PMID:Treatment of renal anemia with recombinant human erythropoietin. 134 20

Hemodynamic response to treatment with erythropoietin has been analyzed on two different groups of patients. The first group of 25 patients was treated with hemodialysis. The second group of 27 was treated with peritoneal dialysis. Both groups were studied before starting the treatment with erythropoietin, after reaching the hemoglobin target point, and after one year of treatment. The following parameters were recorded: basal and hemoglobin target point, time and dosage of response, incidence of arterial hypertension, diastolic and systolic left ventricular diameters, interventricular septum and posterior wall thickness, ejection fraction, fractional fiber shortening, left ventricular mass index, cardiac output index and peripheral resistance index. The incidence of hypertension was 28.8% and, in both techniques, stabilization of left ventricular mass index occurred a year later. When the hemoglobin target point was reached, a decrease in cardiac output and an increase in peripheral resistance was found. These changes were more evident in the group of patients treated with HD. After a year of treatment, both peripheral resistance and cardiac output were similar to basal values in both groups of patients.
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PMID:Could CAPD modulate the hemodynamic changes induced by rHuEPO treatment? 136 42

Treatment with recombinant human erythropoietin (rHuEPO) successfully reverses anemia in uremic patients. Of major concern, however, are blood pressure (BP) increases during rHuEPO therapy, observed particularly in persons with a history of hypertension. To determine whether preexisting hypertension enhances BP increases to rHuEPO, BP responses to 2 wk of rHuEPO or placebo were observed in spontaneously hypertensive rats (SHR) and their normotensive genetic controls (Wistar-Kyoto [WKY] rats. In addition, the role of endothelial-released nitric oxide (NO) in BP alterations caused by rHuEPO through i.v. infusions of endothelium-dependent and independent vasoactive agents were indirectly examined. At trial completion, rHuEPO elevated hematocrit, hemoglobin, and mean cell volume more in SHR than in WKY rats (P less than 0.001). Despite the considerable increase in hematocrit, rHuEPO did not alter BP in either strain. An infusion of NG-monomethyl-L-arginine (L-NMMA), a specific inhibitor of NO formation, elevated BP more in rHuEPO-treated SHR than in identically treated WKY rats (P less than 0.05). Further, the administration of L-arginine caused a greater decrease in blood pressure in SHR than in WKY rats, independent of treatment condition (P less than 0.01). Because changes in BP with endothelium-independent agents were similar across groups, responses to L-NMMA and L-arginine were specific to the endothelium and probably independent of basal BP. Thus, rHuEPO provoked greater erythropoiesis in SHR than in WKY rats but did not elevate BP. L-NMMA stimulated higher BP in SHR treated with rHuEPO, suggesting a compensatory increase in vasodilatory NO synthesis to protect against a hypertensive effect of the drug in SHR.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of erythropoietin on hematocrit and blood pressure in normotensive and hypertensive rats. 139 18

Loss of hypoxic vasodilation has been proposed as a causative factor in the development of hypertension in dialysis patients treated with recombinant human erythropoietin (rHuEPO). Venous occlusion plethysmography was therefore performed on 22 dialysis patients (aged 23 to 71 years, dialysis duration 6 to 260 months, 8 males) before and after correction of anemia with rHuEPO, 50 U/kg 3x/week (Hb: 7.4 +/- 0.3 vs. 10.8 +2- 0.3 g/dl, P less than 0.0001). Hypertension (greater than 15 mm Hg rise in mean BP) occurred in 11 patients. The study was performed while breathing room air and repeated after breathing 60% O2 for 10 to 12 minutes. Before rHuEPO therapy, total blood O2 content increased from 10.01 +/- 0.39 to 10.32 +/- 0.29 ml O2/100 ml blood with breathing 60% O2 (P less than 0.01). After correction of anemia it was 14.65 +/- 0.40 ml O2/100 ml blood on room air (P less than 0.001). There was a significant decrease in forearm blood flow (7.9 +/- 0.5 vs. 6.5 +/- 0.6 ml/min/100 ml tissue, P less than 0.05) and increase in forearm vascular resistance (12.8 +/- 0.1 vs. 16.8 +/- 0.2 mm Hg/ml/min/100 ml tissue, P less than 0.05) with O2 breathing prior to rHuEPO therapy in the blood pressure responders, but no change in these parameters in the group in which blood pressure remained unchanged. When all patients were studied on room air, forearm vascular resistance rose significantly after correction of anemia (13.0 +/- 0.8 vs. 16.3 +/- 0.8 mm Hg/ml/min/100 ml tissue, P less than 0.05), compared with that prior to rHuEPO therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of oxygen breathing and erythropoietin on hypoxic vasodilation in uremic anemia. 145 90

The marvelous effect of recombinant human erythropoietin (EPOCH) on the anemia of the patients suffering from chronic renal failure had been already reported even in the predialysis patients. However, the influence on residual renal function as well as pharmacokinetics of EPOCH in predialysis patients was not clarified yet. Therefore, we made a clinical study of EPOCH in 10 predialysis patients to investigate the clinical effect as well as pharmacokinetics. EPOCH was administered intravenously once a week with the dosage of 3,000-9,000 IU for 8 weeks. All patients showed prominent improvement of anemia. Though no patient show serious adverse effect, two patients showed controllable hypertension accompanying with the increase of hematocrit. Meanwhile, the speed of the deterioration of residual renal function obtained from the regression line by reciprocal of the serum creatinine was not aggravated by the correction of anemia. Pharmacokinetic study revealed that the halflife of EPOCH was extended compared to normal but the degree of extension was same as that of in dialyzed patients. The plasma concentration-time curves showed the pattern of monoexponential disappearance and the area under the curve (AUC 0 to 48 hr.) showed dose-response increase. However, both parameters mentioned above as well as systemic clearance rate did not show any change between those of on day 0 and on day 56. These results no long-term accumulation of EPOCH, though the level of intrinsic erythropoietin was decreased after EPOCH treatment. Thus, the beneficial effect of EPOCH on the correction of anemia was revealed even in the predialysis patients without affecting on residual renal function.
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PMID:[Pharmacokinetics and clinical effect of recombinant human erythropoietin on the anemia of predialysis patients]. 147 10

We studied the hemodynamic changes and the incidence of hypertension after correction of anemia with recombinant human erythropoietin (rhEPO) in 25 hemodialysis (HD) and in 27 continuous ambulatory peritoneal dialysis (CAPD) patients with a mean age of 44.6 years and a mean time on dialysis of 43.6 months. We analyzed basal and final hemoglobin concentrations, time elapsed to reach target hemoglobin, rhEPO dosage, and the following echocardiographic parameters: left ventricular end-systolic and end-diastolic diameters and volumes, posterior wall thickness, interventricular septum, ejection fraction, fractional fiber shortening, cardiac output index, and peripheral vascular resistance index. We did not find any significant difference between HD and CAPD patients in basal and final hemoglobin, concentrations, time elapsed to reach target hemoglobin, dose of rhEPO received for response, and incidence of hypertension. Changes were more evident in HD patients, with a decrease of 15% in cardiac output index and an equal increase of peripheral vascular resistance,. In the patients on CAPD, these variations were less important, with a decrease in cardiac output index of 10% and no significant change in peripheral vascular resistance. Despite both techniques showing the occurrence of hypertension, the left ventricular mass stabilized during the study time. We conclude that CAPD seems to modulate the changes observed in hemodynamic parameters after rhEPO treatment.
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PMID:Effect of recombinant human erythropoietin treatment on hemodynamic parameters in continuous ambulatory peritoneal dialysis and hemodialysis patients. 148 67

Erythropoietin (EPO) is the main regulatory hormone for the control of erythropoiesis. EPO leads to enhanced mitosis and differentiation of erythroid precursors in the bone marrow. The major stimulus for EPO-formation is anaemia of various origin, resulting in an exponential relation between EPO levels and a decrease in haematocrit. Another important stimulus for increased EPO production is a fall of the arterial oxygen tension caused by either cardiopulmonary disorders or by a decrease of the oxygen tension in the inspiratory gas. Human erythropoietin was first isolated and purified from a large amount of urine of patients with aplastic anaemia. After the EPO gene had been cloned and expressed, biotechnically produced recombinant human erythropoietin (rHu-EPO) became available for clinical trials. EPO deficiency appears to be the major cause of renal anaemia, and hence the treatment of these patients is the most important indication for clinical use. Encouraging results in patients whose anaemia is not of renal origin have also been reported, using treatment with rHu-EPO. In preoperative autologous blood donation programmes prior to elective surgery, rHu-EPO therapy improved the amount of donated blood and ameliorated the decrease of haematocrit values. Side effects such as hypertension, thrombosis, hypercalcaemia, elevated liver enzymes were rare and were mostly related to the underlying disease.
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PMID:[Erythropoietin--physiology and therapeutic potentialities]. 148 69


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